| Step | Hyp | Ref | Expression | 
|---|
| 1 |  | frgrwopreg.a | . . . . . 6
⊢ 𝐴 = {𝑥 ∈ 𝑉 ∣ (𝐷‘𝑥) = 𝐾} | 
| 2 | 1 | reqabi 3459 | . . . . 5
⊢ (𝑥 ∈ 𝐴 ↔ (𝑥 ∈ 𝑉 ∧ (𝐷‘𝑥) = 𝐾)) | 
| 3 |  | fveqeq2 6914 | . . . . . . 7
⊢ (𝑥 = 𝑎 → ((𝐷‘𝑥) = 𝐾 ↔ (𝐷‘𝑎) = 𝐾)) | 
| 4 | 3, 1 | elrab2 3694 | . . . . . 6
⊢ (𝑎 ∈ 𝐴 ↔ (𝑎 ∈ 𝑉 ∧ (𝐷‘𝑎) = 𝐾)) | 
| 5 |  | eqtr3 2762 | . . . . . . . . 9
⊢ (((𝐷‘𝑎) = 𝐾 ∧ (𝐷‘𝑥) = 𝐾) → (𝐷‘𝑎) = (𝐷‘𝑥)) | 
| 6 | 5 | expcom 413 | . . . . . . . 8
⊢ ((𝐷‘𝑥) = 𝐾 → ((𝐷‘𝑎) = 𝐾 → (𝐷‘𝑎) = (𝐷‘𝑥))) | 
| 7 | 6 | adantl 481 | . . . . . . 7
⊢ ((𝑥 ∈ 𝑉 ∧ (𝐷‘𝑥) = 𝐾) → ((𝐷‘𝑎) = 𝐾 → (𝐷‘𝑎) = (𝐷‘𝑥))) | 
| 8 | 7 | com12 32 | . . . . . 6
⊢ ((𝐷‘𝑎) = 𝐾 → ((𝑥 ∈ 𝑉 ∧ (𝐷‘𝑥) = 𝐾) → (𝐷‘𝑎) = (𝐷‘𝑥))) | 
| 9 | 4, 8 | simplbiim 504 | . . . . 5
⊢ (𝑎 ∈ 𝐴 → ((𝑥 ∈ 𝑉 ∧ (𝐷‘𝑥) = 𝐾) → (𝐷‘𝑎) = (𝐷‘𝑥))) | 
| 10 | 2, 9 | biimtrid 242 | . . . 4
⊢ (𝑎 ∈ 𝐴 → (𝑥 ∈ 𝐴 → (𝐷‘𝑎) = (𝐷‘𝑥))) | 
| 11 | 10 | imp 406 | . . 3
⊢ ((𝑎 ∈ 𝐴 ∧ 𝑥 ∈ 𝐴) → (𝐷‘𝑎) = (𝐷‘𝑥)) | 
| 12 | 11 | adantr 480 | . 2
⊢ (((𝑎 ∈ 𝐴 ∧ 𝑥 ∈ 𝐴) ∧ (𝑏 ∈ 𝐵 ∧ 𝑦 ∈ 𝐵)) → (𝐷‘𝑎) = (𝐷‘𝑥)) | 
| 13 |  | frgrwopreg.v | . . . 4
⊢ 𝑉 = (Vtx‘𝐺) | 
| 14 |  | frgrwopreg.d | . . . 4
⊢ 𝐷 = (VtxDeg‘𝐺) | 
| 15 |  | frgrwopreg.b | . . . 4
⊢ 𝐵 = (𝑉 ∖ 𝐴) | 
| 16 | 13, 14, 1, 15 | frgrwopreglem3 30334 | . . 3
⊢ ((𝑎 ∈ 𝐴 ∧ 𝑏 ∈ 𝐵) → (𝐷‘𝑎) ≠ (𝐷‘𝑏)) | 
| 17 | 16 | ad2ant2r 747 | . 2
⊢ (((𝑎 ∈ 𝐴 ∧ 𝑥 ∈ 𝐴) ∧ (𝑏 ∈ 𝐵 ∧ 𝑦 ∈ 𝐵)) → (𝐷‘𝑎) ≠ (𝐷‘𝑏)) | 
| 18 |  | fveqeq2 6914 | . . . . . 6
⊢ (𝑥 = 𝑧 → ((𝐷‘𝑥) = 𝐾 ↔ (𝐷‘𝑧) = 𝐾)) | 
| 19 | 18 | cbvrabv 3446 | . . . . 5
⊢ {𝑥 ∈ 𝑉 ∣ (𝐷‘𝑥) = 𝐾} = {𝑧 ∈ 𝑉 ∣ (𝐷‘𝑧) = 𝐾} | 
| 20 | 1, 19 | eqtri 2764 | . . . 4
⊢ 𝐴 = {𝑧 ∈ 𝑉 ∣ (𝐷‘𝑧) = 𝐾} | 
| 21 | 13, 14, 20, 15 | frgrwopreglem3 30334 | . . 3
⊢ ((𝑥 ∈ 𝐴 ∧ 𝑦 ∈ 𝐵) → (𝐷‘𝑥) ≠ (𝐷‘𝑦)) | 
| 22 | 21 | ad2ant2l 746 | . 2
⊢ (((𝑎 ∈ 𝐴 ∧ 𝑥 ∈ 𝐴) ∧ (𝑏 ∈ 𝐵 ∧ 𝑦 ∈ 𝐵)) → (𝐷‘𝑥) ≠ (𝐷‘𝑦)) | 
| 23 | 12, 17, 22 | 3jca 1128 | 1
⊢ (((𝑎 ∈ 𝐴 ∧ 𝑥 ∈ 𝐴) ∧ (𝑏 ∈ 𝐵 ∧ 𝑦 ∈ 𝐵)) → ((𝐷‘𝑎) = (𝐷‘𝑥) ∧ (𝐷‘𝑎) ≠ (𝐷‘𝑏) ∧ (𝐷‘𝑥) ≠ (𝐷‘𝑦))) |